1. Field of the Invention
The present invention relates in general to cartons, and more particularly, relates to a carton of unitary structure which is adapted for heating food, especially frozen food, in a microwave oven.
In recent years, microwave ovens have assumed an important position in the kitchens of numerous homeowners, inasmuch as they enable foods, various kinds of foods, such as frozen food consisting of vegetables and even complete meals to be quickly and conveniently heated and/or cooked in microwave ovens.
In particular, modern homemakers who frequently prepare meals for a household while concurrently being employed in a full-time job in industry or commerce, have recognized the convenience of microwave cooking and heating of frozen foods and the like. However, in order to do so, some labor-intensive steps must be undertaken. In essence, the food must be removed from the package, irrespective as to whether it is constituted of a plastic or paperboard carton or a foil tray, arranged in a dish transparent to microwaves and possessing the necessary strength and then heated in the microwave oven. This step is necessary since various objects, such as aluminum foil trays or other metal receptacles containing the food cannot be employed in microwave ovens; whereas other types of cartons are not suitable for the retention of liquids. On the other hand, cartons which are designed to hold liquids, utilize adhesives, which when subjected to the heat of the microwave oven frequently produce off-tastes and generate off-odors in the foods.
2. Discussion of the Prior Art
In order to improve upon the structure and the convenience in the utilization of microwave cartons, particularly cartons which can be opened prior to and/or during the cooking sequence to enable access to the carton contents, and then reclosed so as to effectively seal in the food, various types of microwave cartons have been developed in the art.
Thus, Ielmini U.S. Pat. No. 4,687,104 discloses a microwave carton possessing a top and front flap structure parallel spaced inner and outer score lines to define operable and recloseable top and front flap portions through the formation of tearable joints. The top flap portion is configured to allow for the retention of a full-strength U-shaped top surface to enable lifting of the carton and contents therein without affecting the intergrity of the carton structure. This type of carton, while enabling the heating of foods in a microwave oven, does not enable the sealing reclosure of the front flap portion because of the incorporation of the parallel spaced tear joint lines, and moreover, in one embodiment, includes a tab-receiving slit in the sidewall thereof which will permit liquids to escape from the carton during the heating of the carton contents in a microwave oven.
Meroszek U.S. Pat. No. 4,594,492 pertains to a microwave package in the nature of a carton which incorporates structure for browning foods in the carton when cooked in a microwave oven. There is no disclosure of a carton which allows for the resealing thereof prior to or after heating the carton contents in the oven so as to inhibit the egress of any liquids from the carton.
Smith U.S. Pat. No. 3,167,238 discloses a recloseable carton which incorporates top and front flap portions which are openable by separation from the remaining carton along tear lines and formations. The carton may then be reclosed by tucking in of the separated front flap portion behind a front carton panel. Although this carton is basically recloseable, it is of an adhesively-sealed configuration which is not readily adapted for use in the heating or cooking of foods therein in a microwave oven.